Title:
ZOOM LENS BARREL
Document Type and Number:
Japanese Patent JPH03217804
Kind Code:
A
Abstract:
PURPOSE:To suppress the play of a cam cylinder in the direction of the optical axis and to attain stable focusing so that a subject image does not come to out of focus by providing an elastic piece which presses the end surface of the cam cylinder in the direction of the optical axis. CONSTITUTION:The outer peripheral surface of the cam cylinder 22 abuts on the inner peripheral surface part 23b of a fixed lens barrel 21 and is restrained at right angles to the optical axis F. One of both end surfaces of the cam cylinder 22 is restrained in the direction of the optical axis F by the inside end surface 21a of the fixed lens barrel 21 and the other end surface is pressed while abutting on the elastic piece 23 and restrained in the direction of the optical axis F. The play of the cam cylinder 22 in the direction of the optical axis F can be suppressed irrelevantly to variation in the clearance DELTAl of the cam cylinder 22 in the direction of the optical axis F with ambient temperature. Therefore, when the zoom direction is changed, the follow-up performance of the cam cylinder 22 is excellent, the subject image never comes to out of focus during zooming operation, and the quantity of power variation does not vary owing to an attitude difference when the zoom lens barrel is panned vertically. Therefore, the stable focusing is made possible without reference to the ambient temperature.
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Inventors:
TERASAKA TAKASHI
YABUKI TAKANOBU
YABUKI TAKANOBU
Application Number:
JP1412290A
Publication Date:
September 25, 1991
Filing Date:
January 23, 1990
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G02B7/04; (IPC1-7): G02B7/04
Attorney, Agent or Firm:
Shigetaka Awano (1 person outside)